825 research outputs found

    Application of a Novel Synergetic Control for Optimal Power Extraction of a Small-Scale Wind Generation System with Variable Loads and Wind Speeds

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    © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).The synergetic control technique (SCT) has the solution for understanding the symmetry inherent in the non-linear properties of wind turbines (WTs); therefore, they achieve excellent performance and enhance the operation of the WT. Small-scale WTs are efficient and cost-effective; they are usually installed close to where the generated electricity is used. This technology is gaining popularity worldwide for off-grid electricity generation, such as in rural homes, farms, small factories, and commercial properties. To enhance the efficiency of the WT, it is vital to operate the WT at its maximum power. This work proposes an efficient and fast maximum power point tracking (MPPT) technique based on the SCT to eradicate the drawbacks of the conventional methods and enhance the operation of the WT at the MPP regardless of wind speed and load changes. The SCT has advantages, such as robustness, simplified design, fast response, no requirement for knowledge of WT characteristics, no need for wind sensors or intricate power electronics, and straightforward implementation. Furthermore, it improves speed convergence with minimal steady-state oscillations at the MPP. The investigated configuration involves a wind-driven permanent magnet synchronous generator (PMSG), uncontrolled rectifier, boost converter, and variable load. The two converters are used to integrate the PMSG with the load. Three scenarios (step changes in wind speed, stochastic changes in wind speed, and variable electrical load) are studied to assess the SCT. The results prove a high performance of the suggested MPPT control method for a fast convergence speed, boosted WT efficacy, low oscillation levels, and applicability under a variety of environmental situations. This work used the MATLAB/Simulink program and was then implemented on a dSPACE 1104 control board to assess the efficacy of the SCT. Furthermore, experimental validation on a 1 kW Darrieus-type WT driving a PMSG was performed.Peer reviewe

    Role of Seismic Refraction Tomography (SRT) in bedrock mapping; case study from industrial zone, Ain-Sokhna area, Egypt

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    In this study, eighteen compressional P-wave seismic refraction profiles survey was conducted on the western side of the Gulf of Suez, Egypt, to map bedrock topography, which is vital information in foundation pole placement and design for large factory construction. The configuration of the seismic survey consists of 10 metres geophone intervals (12 and 24 channels) with a total survey length of 3150 metres survey length. The seismic compressional wave velocity distribution reveals three layers ranging from (400 to 1100 m/s), (1200 to 2000 m/s), and (2200 to 3500 m/s). According to the data, the first low-velocity layer represents unconsolidated Wadi sediments. The second layer, on the other hand, comprises consolidated Wadi sediments, while the third layer comprises fractured to intact sandstone bedrock. The thickness of the first layer is believed to be between 0.5 and 10 m, while the thickness of the second layer is between 8.5 and 25 m. Pseudo-3D model of velocity distribution was constructed, revealing the presence of several low-velocity zones at a depth ranging from 15 to 32 m. Then, the topography of the non-rippable sandstone rock mass was mapped utilizing 3-D model. Finally, the correlation between seismic refraction tomography (SRT) results and nearby well logging dataset drilled by the Egyptian Geological Survey and Mining Authority (EGSMA) matched quite well. It may be inferred that, up to a depth of 15 to 32 metres, there is a high-velocity rock layer suitable for constructing deep foundations for multiple levels of the mega factory

    Perspective Chapter: The Toxic Silver (Hg)

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    In the late 1950s, residents of a Japanese fishing village known as “Minamata” began falling ill and dying at an alarming rate. The Japanese authorities stated that methyl-mercury-rich seafood and shellfish caused the sickness. Burning fossil fuels represent ≈52.7% of Hg emissions. The majorities of mercury’s compounds are volatile and thus travel hundreds of miles with wind before being deposited on the earth’s surface. High acidity and dissolved organic carbon increase Hg-mobility in soil to enter the food chain. Additionally, Hg is taken up by areal plant parts via gas exchange. Mercury has no identified role in plants while exhibiting high affinity to form complexes with soft ligands such as sulfur and this consequently inactivates amino acids and sulfur-containing antioxidants. Long-term human exposure to Hg leads to neurotoxicity in children and adults, immunological, cardiac, and motor reproductive and genetic disorders. Accordingly, remediating contaminated soils has become an obligation. Mercury, like other potentially toxic elements, is not biodegradable, and therefore, its remediation should encompass either removal of Hg from soils or even its immobilization. This chapter discusses Hg’s chemical behavior, sources, health dangers, and soil remediation methods to lower Hg levels

    Investigation of the Ameliorating Effect of Copper Albumin Complex on Lysyl oxidase in monosodium iodoacetate -Induced Knee Osteoarthritis in Rats

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    Knee osteoarthritis (KOA) is a common type of joint degeneration which causes progressive damage of the joint structure and has less therapeutic options. It has been found that oral consumption of Copper Albumin Complex as anti-inflammatory drug has a positive effect on the treatment of joint deterioration. The present study aimed to investigate the effect of oral administration of Copper Albumin Complex (cu-albumin complex) on Lysyl oxidase (LOX) which acts as a protective factor in KOA. Fifty adult albino rats were divided into 3 groups: negative control (10 normal rats); positive control (20 rats with KOA which left without induction treatment); and treated group (20 rats with KOA which treated with administration of copper albumin complex). Treated and untreated arthritic groups were subdivided equally into mild and severe groups (10 rats for each) according to the severity of clinical signs. KOA was induced by intra-articular injection of monosodium iodoacetate (MIA). At the experimental end, the joints were examined histopathologically and immunohistochemically after cervical dislocation of rats. It was observed that the treatment with CU- was effective in reducing disease severity and in improvement of Lysyl oxidase KOA. It was concluded that Copper albumin complex has a positive effect in the improvement of LOX of Knee joint cartilages of rats affected by osteoarthritis (OA)

    Consumer trust and confidence in the compliance of Islamic banks

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    Islamic banks compete with traditional (non-Islamic) banks for customers. This article aims to provide insight into why some Muslims choose to bank with Islamic banks in Pakistan, while others do not. Specifically, it addresses the questions: to what extent are trust and confidence active influencers in the decision-making process, are they differentiated or are they one of the same? Also how does the Pakistani collective cultural context further complicate the application of these concepts? For the purposes of this article trust refers to people and their interpersonal or social relations whereas confidence concerns institutions such as banks. Drawing on interviews with Muslim consumers in Pakistan, this study provides further insight into consumer behaviour within financial services and specifically Islamic banking and contributes to our theoretical understanding of the concepts of trust and confidence

    Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

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    BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

    Global economic burden of unmet surgical need for appendicitis

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    Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US 92492millionusingapproach1and92 492 million using approach 1 and 73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was 95004millionusingapproach1and95 004 million using approach 1 and 75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially
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